ABGs (acid-base met/resp)

Question 1

Arterial Blood Gases

Answer 1

• Gasses such as CO2 and O2
• When thinking of CO2, think ACID and respiratory
• Too much CO2 = hyperventilation
• Too little CO2 = hypoventilation
• Normal CO2 levels = 35-45mmHg (acid)
• Normal O2 levels = 80-100mmHg

Question 2

pH

Answer 2

• Acidosis = below 7.35
• Alkalosis = above 7.45
• Normal = 7.35-7.45

Question 3

HCO3

Answer 3

• HCO3 is a BASE
• HCO3 is how body increases pH
• Increased pH = then increase HCO3 or decrease amount of acid (CO2) through hyperventilation
• Normal HCO3 = 22-26 meq/L (base)

Question 4

Respiratory Acidosis

Answer 4

• Lungs cannot remove enough of the CO2 causing excess CO2 (acid) in body
• pH less than 7.35
• PaCO2 > 45 mmHg (“R.O.M.E”)
• Symptoms = confusion, agitation/anxiety, restlessness, blurred vision, seizures (“CARBS”)

Question 5

Respiratory Alkalosis

Answer 5

• Lungs remove too much CO2 causing deficient CO2 (acid) in body
• pH is more than 7.45
• PaCO2 is < 35 mmHg (“R.O.M.E”)
• Symptoms = numbness/tingling, orthostatic hypotension, confusion, anxious, rapid breathing, dizziness, seizures (“NO CARDS”)

Question 6

Metabolic Acidosis

Answer 6

• Kidneys do not produce enough HCO3 (base) causing an excess amount of acid in body
• pH is less than 7.35
• HCO3 (base) is < 22 meq/L
• Symptoms = stupor, hyperkalemia, arrhythmias, muscle twitching, emesis, decreased cardiac output/contractibility (“SHAMED”)
• Side note = diabetic ketoacidosis is associated with this

Question 7

Metabolic Alkalosis

Answer 7

• Excess production of HCO3 by kidneys
• pH is > 7.45
• HCO3 is > 26 meq/L
• Common conditions associated with this on NPTE would be vomiting, antacids, diuretics
• Symptoms = tetany, tachycardia, tremors, tingling (“the 4 T’s”)

Question 8

Uncompensated

Answer 8

• pH is normal and one thing is out of range (PaCO2 or HCO3)

Question 9

Compensated

Answer 9

• pH is normal but both PaCO2 and HCO3 are out of range

Question 10

Partially Compensated

Answer 10

• Everything is out of range

Question 11

Steps to solving ABG questions on the NPTE…

Answer 11

(1) look at pH (above 7.45 is alkalosis and below 7.35 is acidosis)
(2) determine respiratory or metabolic (use “ROME” = respiratory opposite metabolic equal)
(3) determine compensation (if pH is within normal ranges and both PaCO2 and HCO3 are out of range then its compensated, however, if everything is out of range it is partially compensated, and if pH is normal and one thing is out of range then its uncompensated